Audio/video codecs by ACS

[Richard Thorpe]

Hi there, do you have any detailed information on the audio and video codecs used by ACS when embedded in a website/JS. Including maximum bitrate if possible

[#2]

@Richard Thorpe, we use G.722, SILK and G.711 (mostly in Azure direct routing for SBC compatibility). Detailed BW requirements and bitrates are documented here https://docs.microsoft.com/en-us/azure/communication-services/concepts/voice-video-calling/network-r...

[#3]

Hi Nikolay,

Thanks for getting back to me so quickly. Unfortunately the link doesn’t talk to maximum bitrate only required bandwidth, do you have any more specifics?
Also, do you know when ACS will use the Satin codec recently introduced by Teams? - my thought process being that I presumed they were powered by the same engine

[#4]

@Richard Thrope, thanks. Please see in the table. https://docs.microsoft.com/en-us/azure/communication-services/concepts/voice-video-calling/network-r... E.g. with 1.2 Mbps you can get HD720 with 30 fps. Note for JavaScript you cannot go beyong 720p at 30 fps, for Native we can go up to 1080p at 30 fps. Is there other parameters you are looking for?

[#5]

Thanks Nikolay,

My understanding is that G.722 offers an audio sample frequency of 16kHz which results in a maximum 8kHz output. SILK, I believe, was as a result of the Skype acquisition in 2011 which created super-wideband audio capable of reproducing 12kHz from a 24kHz sampled frequency.

The exciting part of the MS proprietary "Satin" codec was that whilst it currently provides 16kHz output from a 32kHz sample frequency, it was mentioned that in the coming months this would be increased to provide 'full-band' audio at 48kHz. A standard CD has a 44.1kHz sample frequency, so this update would significantly improve audio output. Currently, competitors such as Zoom are already offering this quality so I'm keen to understand when we can become competitive?

[#6]

Streaming services such as Spotify use MP3 audio and provide various bitrates from 128Kbps to 320Kbps. Bitrate is effectively the number of kilobits of data streamed per second. This sort of information would be very helpful.

[#7]

Thanks. We are working on adding more codecs in upcoming quarter. I noted the level of details you want to have in the documentation. We will get these details in docs

[#8]

Finally, my understanding is that ACS is using the H.264 and VP8 video codec for P2P connections delivered over WebRTC - sadly, this is the factor that limits video quality to 720p in the browser. Technologies like Google Meet (also leveraging WebRTC) have implemented the VP9 codec used by YouTube which gives them 1080p (and in fact I think 4K) video quality. Is there any plans for Microsoft to improve the existing service too?

[#9]

Thanks, we are working on getting more codecs supported by ACS. Thank you for the feedback.